Transformer specifications

[kashew]

Can someone tell me if there is a reference that provides typical distribution transformer impedances? I'm looking for %Z and either X/R ratios or %X and %R values.

The X/R table in IEEE red book is not adequate.

 

[weh3]

The Navy has some tables at

http://www.ccb.org/docs/NAVGRAPH/16272.pdf

Tables PM-1, 2, and 3 are for the energy cost per kWh of x<$.04, .04<x<$.08, and x>$.08 respectively.

Let me know if that helps.

Regards,
William

 

[dpc]

http://www.geindustrial.com/products/applications/GET-3550F.pdf

See Table 11 if you're looking for oil-filled distribution type transformers.

I would also recommend Conrad St. Pierre's book "A Practical Guide to Short Circuit Calculations".

 

[kashew]

This is exactly what I have been searching. I was looking through the rest of the document and have a question. Table 17 lists cable resistance and reactance in magnetic and non-magnetic conduit. Are cable resistance and reactance for direct buried cable the same as the non-magnetic conduit values? If not where can I find some values for direct buried?
Thanks

The NAVGraph document will also be useful to me since it has transformer losses. Thanks William!

 

[davidbeach]

You can think of the "non-magnetic conduit" values as being "not in magnetic conduit" values. Once the conductors are no longer enclosed in a magnetic container, what is around the conductors has much less impact on impedance than does the relative location of the conductors.